Mixing machine



jan, 13, 1925.

. 1,523,184 E. EGER MIXI NG MACHINE Filed March 6 1924 Patented dan. 13, 1925..4

' UNITE-D' STATES PArsNr oFics.

ERNST TIGER, 0F DETROIT, MICHIGAN, ASSIGNOR TO MORGAIf WRIGHT, QFD

MICHIGAN, A CORPORATION 0F MICHIGAN'.

momma.

Application led March @1924. Serial No. 697,188.

To'nll *whom t man concern.' l A Be it known that I, ERNST EGR, a citizen of the United States, residing at Detroit, county of Wayne, State oflMichi an, have invented a new and useful Mixing achine, of which the following is a' full, clear, and exact description'. Y j 1 r 1 This invention relates to mixing machines for plastic materials and has for its principal object the 4devising of means whereby the plastic material or materials may be thoroughly' milled or mixed in a shorter period of time and more economically than heretofore with the employment of similar types of machines.V v

Y Referring to the drawings forming a par of this specification,

Fig. 1 is a longitudinal sectional view of a machine embodying the inventioh;l

Fig. 2 is a transverse sectional view of the machine;

Fig. 3 is a fragmental view of the interior wall of the mixing chamber showing ive of the grooves formed therein; and

Fig. 4 is an enlarged diagrammatic view off-.twovof the grooves shown in Figure tt.`

The invention viewed broadly comprises a mixing chamber, means .for mixing the material while conveying it through the chamber from a point or points of lesser to a point or points of greater pressure, and a passageway having aA portion of its length of increasing depth or cross-sectional area for conveying the material, after it has been so moved, from a point or points of greater l pressure to a point or points of lesser pres'- sure, the movement of the material through the passageway being due to the pressure of the material behind it.

ln the preferred embodiment a screw is employed as the means for mixingthe -material and moving it' along the chamber.

Machines of this general type are shown in patents granted tof me, Nos. 1,427,271-2 and reference is made thereto for a more detailed description of the construction of such machines, the present, invention being an improvement thereof. In the present:`

embodiment the invention is illustrated in connection with a double end mixer employ-l ingarightand left-threaded screw which is the type of machine shown in the abovementioned Patent No.I 1,427 ,271. The machine briey described includes a mixing `chamber 1 of cylindrical formation having feed or chargingopenings 2, 3, llocated at 4its ends. and preferably at the top, and a 'discharging opening 4f preferably located at the center near the bottom. A shaft 5, carryingl rightand left-threaded screws 6 and 7, is revolubly mounted in the cylinder and has secured on an en extendin from the cylinder a gear 8 which. is in mes with a driving pinion 9 secured ona drive shaft 10 which is drivenby any desired source of power for revolving the screws. The screws are of decreasing pitch from the charging ends of the mixing chamber toward the center and are preferably symmetrically arranged on the shaft so that they will meet as shown at 11 at the center. 'lhe screws are shown of substantially the same diameter as the cylinder at the charging ends and of lesser diameter throughout the remainder of their lengths for reasons more fully described in my before-mentioned patents. y

Un account of the varying pitch of the screws the material as it is moved along the mixing chamber will be under a continually increasing pressure from its starting points at the charging ends ofthe screws where it is of least pressure to the point of least pitch, in the present embodiment, Iat the center of the chamber where it is of greatest l pressure. I have found that if a passageway is opened to the material at a point of relatively high pressure and the passageway has for a considerable length therefrom a gradually increasing depth or cross-sectionalarea that it will aord an avenue of travel 'for the materialof decreased resistance, and that therefore, as the material is ever seeking a path of less resistance, it will readil enter such a passageway at the point of re atively high pressure and be moved alon due to the pressure of the material behin the part so moving. Furthermore, I have found that if the passageway is o ened to a point or points 'in the chamber w ere the materia-l is under less pressure as ata charg- 'ing end of the screw that the material will move along the passageway and leave it at such point .or points to again be brought under the direct action of the screw at such point of lesser pressure and by the action of the screw .will be further mixed and moved along the chamber to a place of higher pressure where it again enters the passageway, and the operation 1s` repeated. This will continue until the material 1s thorl oughly mixed and will require much less time than is possible with prior machines employing a. screw.

In the practical carrying out of the in vention the passageway,l is preferably composed of a plurality of grooves formed in the wall of the cylinder having their depth, or

cross-sectionalarea, or what may be termed for convenience their cross-sectional dimension, increasing for a considerable distance of their length from the pointor points where they receive'the material, that is to say, from the point or, points'of greatest pressure toobtained very satisfactory results from a V- shaped groove of increasing depth .or increasing cross-sectional area extending from a point of greater pressure for a suitable distance and then of decreasing depth and cross-sectional area for the remainder of the distance. The side walls of such a groove diverge longitudinally until the greatest depth and cross-sectional area is reached and then converge until they vanish or merge in the wall of the cylinder. By this construction the material is .easily moved entirely out 'of the groove and the groove cleaned inthe most satisfactory manner.

The drawings show a preferred embodiment of my invention devised for mixing together two plastics such as rubber or rubber compounds, one being fed into the chamvber through the charging opening 2 and the rother through the charging opening 3. The

passageway for conveying the materials from the poi t of greatest pressure is composed of a plurality of grooves formed in the wall of the'chamber and will vary in number, size, and arrangcmeht dependentlargely upon the natures of the materials to be treated. For instance, I have found in general very satisfactory results to fol- Llow by the crowding of the grooves more at t-'he top of the cylinder than elsewhere and providing them with greater depths at the top of the cylinder than elsewhere. .In the present embodiment the grooves 12 are shown of similar construction but alternately reversed, to provide two series 13- and 14, the grooves o one series alternating with the grooves of the other. The grooves of both series are V-shaped in cross-section. The grooves merge at both ends mto a pomt and vanish'in the wall of the cylinder therev scribed. The grooves increase in depth anday cross-sectional area as they-progress fromv the ends, the series 13 reaching the greatest depth and cross-sectional area at a con-- siderable distance to the right of the center lineas viewed in Figures 3 and. 4, and the series 14 reaching the greatest depth and cross-sectional area at a considerable distance tothe left of the center line. It will be notedpthat the grooves increase in depth,

directly with the increase of their crosssectional 'a1-eas. l The greatest depth and cross-sectional area to be employed and thc position of same relative to the center lim` or point of greatest pressure will depend to a considerable extent upon `the nature ot the materials to be, treated.

The operation of amachine of the double end-type involving the present invention is' as follows The chamber is charged with the plast-ics as for instance rubber or rubber compound in a plastic form through the charging openings 2 and 3, and these open- .ings Iand the discharging opening are then closed.. For purposesof contrast and clearness of illustration the two charges will he termed hereafter the white compoundl whichl is presumed to be charged through the charging opening 2 and the black compound presumed to be charged through the charglng opening 3. These two 'compounds lwill be mixed and moved along the chamber by their respective screws from their points of least pressure where the pitch'is the greatest at the char ing end to the point of greatest pressure w ere the pitch is the leastl `at the center. Here the two materials meet and being under the maximum ressure they seek a path of less pressure or ess resistance. Accordingly the white compound will continue the general direction of its movement throu h the chamber and will be'forced to the rlght of .the centerline and into yand along the passageway rformed by the series of rooves 13 to the right of the center line. am? the black compound will likewise continue the eneral direction of its mo vement through tige chamberand will be forced to the left of the center line and into 'and' along the passageway formed hy the series of grooves 14. As these grooves are increasing m depth and cross-sectional dimension they continually offer less resistance until the point of greatestdepth and cross-sectional area is reached and the two materials will accordin ly readily move along l these grooves ue to the pressureA of the material behind them until the point of greatest depth n and cross-sectional area is reached. At this point the grooves gradually decrease in negarse cross-sectional area and depth until they vanish at their ends in the. wall of the cham' ber. The materials will continue theirmovement through lthese portions of the grooves due to the pressure behind them until they are forced out of the grooves and are brought again under the action of the screw"V but at the opposite end bf the chamber, the

black material being thus mixed or blended with the white material being milled bythe screw at the left, and the white material being mixedor blended with the black material being milled by the screw at the. right.

This takin of a relatively small quantity ,of the material from the right-hand side of the machine and mixing it with'the larger' quantity of the material at the left-hand side, and vice versa, the taking of a small quantity of material from the left-hand side and mixing it with the larger quantity at the right-hand side is continually7 going on as the screws revolve until the two materials are thoroughly mixed and milled together. This requires much less time to accomplish and can be done at much less expense than lesser to a point or points of greater pres' sure if ooves such as have been described are emp oyed a very material saving in time and expense will be effected in the mixing and blending of the rastic materials. l

As many apparent y widely different embodiments 'of this invention may be made without departing from the spirit thereof,`

it is to be understood that I do not intend to limit myself to`the specific form of the invention as set forth except as indicated in the appended claims;

Having thus described my invention what l claim and desire to protect by Letters Patent is:

1. A Amachine for mixing plastic material, comprising a mixing chamber, means for mixing the materialV while moving it along the chamber, and a passageway open Ato said chamber for receiving and convey- ,ing the material after it has been so moved,

`said passageway being of varying cross-section dimension and 'having its exit end opening into said chamber.

2. A machine for mixing plastic material, comprising a mixing chamber, means for mixin the material while moving it :from a point of lesser re'ssiire to a point of greater pressure, an a passageway et varying cross-sectional dimension for conveying the material from a point of greater pressure to .a point 'of lesser pressure.

3. A machine for mixing plastic material, comprising a, mixing chamber, a screw revolubly supported therein, means -for yrevolving the screw whereby the material may be mixed while being moved along the chamber, and a passageway for conveying the kmaterial after it has been so moved, said assa ewa bein ofvar inw cross-sectional imension and having its exit end opening into said chamber.

4. A machine for Imixing plastic material, comprising a mixing chamber, means for mixing the material while moving it i from a point of lesser pressure to a point of greater pressure, and a passageway ot varying cross-sectional dimension tor conveying the material from the point ot' greater pressure back to the point ot' lesser J pressure.

5. A machine for mixing plastic material, comprising a mixing chamber, meansA for mixingI the material while moving it along the chamber from .points of lesser pressure to points of greater pressure. passageways of varying cross-sectional dimenvsion foi-'conveying the material from points of Vgreater pressure to points of lesser pressure.

` 6. A machine for mixing .plastic matef rial, comprising a mixing chamber, a double screw revolubly supported therein, means for revolving the screw whereby the material may be mixed while being moved along the chamber from points of esser pressure to points of greater pressure, and passageways'o'f varyingl cross-sectional dimensions 'for conveying t e material from points of greater pressure to points of lesser pressure.

7. A machine; for mixing plastic material, comprising a mixingv chamber, means for mixing the material while moving it along ythe chamber, and apassageway comprising a plurality of grooves formed in the wall of the chamber for conveying the material after it has been so moved, said grooves bein of varying cross-sectional dimensions and having their exit ends openling into said chamber.-

8. A machine for mixing plastic material, comprising a chamber, a screw revolubly supported inthe chamber, means for revolvin the screw whereby the material will be mixed while moving along the chamber, and a vpassageway comprising a plurality of grooves Jformed in the wall of the chamber or conveying the material after it has been so moved, said grooves being of varying Across-sectional dimensions and having their exit ends opening into saJid chamber.

9. A machine for mixing plastic matelrials, comprisin a mixing chamber, a dourials will be moved from points of lesser pressure .at the outer ends ofthe screw to points of greater pressure at the center of -toward one end of the chamber and the other series increasing toward the opposite end ofthe chamber. l l0. Ajmachine for mixiner plastic matev rial, comprising a mixing'ciamber, means for mixingthe material While moving it along thevchamber, and a passageway comprising a plurality of grooves 'formed in the chamber in the same generaldirection as thepath of movement of the material, said grooves increasing from each end in crosssectional dimension to a point of greatest cross-sectional dimension between the ends.

11. A machine for mixin plastic material, lcomprising a mixing c amber, means for mixing the material while moving itvr along the chamber, and a passageway comprising a plurality of grooves formed in the chamber in the same general direction as the path of movement of the material, said grooves increasing lfrom each end in crosssectional dimension, part of said grooves reaching their greatest cross-sectional dimension`on one side of the .center line and another part of said grooves reaching their :,easasc greatest cross-sectional dimension on opposite side of said center line.

12. A machine for'mixin plastic material,` comprising a mixing c amber, means for mixing the material while, moving it along the chamber anda assageway comprisin .a plurality of ,p -shaped grooves orme in t e chamber inthe same general the direction as the pathv ofA movement of the v material, said grooves increasing from each end in cross-sectional' dimension to a point of greatest cross-sectional dimension between the ends.

' 13. A machine for mixin plastic material, comprising a mixing c iamber, means for mixing the material while moving it alongfthe chamber, and apassageway comprisinfr a lurality of V-shaped grooves forme in t e chamber' in `the same general direction as the path of movement of the material, said'grooves increasing from each end in cross-sectional dimension to a point of greatest cross-sectionall dimensionl between the ends, the sides of said grooves converging from said point to the ends of the grooves where they vanish at the Wall of the chamber.

Signed at Detroit, county of Wayne, State ot' Michigan, this 28th day of February ERNST EGER. 

